2849 - Carbides, whether or not chemically defined:

This HTS category, 2849, encompasses carbides, which are chemical compounds formed by the combination of carbon with a less electronegative element. These substances can be either chemically defined or not, indicating that the classification applies to both pure, stoichiometric compounds as well as mixtures that exhibit carbide characteristics. The scope of this heading is broad, covering a range of inorganic materials essential in various industrial applications, from metallurgy to the production of advanced ceramics.

Unlike sibling categories at the root level which primarily deal with live animals (Chapters 01 through 05), Chapter 28 focuses on inorganic chemicals. Carbides, classified under 2849, are distinct from other inorganic compounds in Section VI due to their unique carbon-metal or carbon-metalloid bonding. Their metallic or semi-metallic nature and often extreme hardness differentiate them from simple inorganic salts, oxides, or hydroxides.

Within heading 2849, further subclassification is based on the specific elemental composition of the carbide. Subheadings distinguish between carbides of calcium (2849.10), silicon (2849.20), and a residual category for "Other" carbides (2849.90). This breakdown allows for more precise classification based on the primary metal or metalloid component, which significantly influences the carbide's properties and intended uses.